The present invention relates to devices for reducing or preventing the discharge of harmful substances from an area isolated by such a device to the surrounding environment.
Foreseeable applications for the present invention especially include the isolation of air contaminated by potentially disease-carrying blood or airborne aerosol particles from a patient during a medical procedure, but can also include applications in laboratories, industrial environments and the like, where the isolation of an area for health and safety reasons is desirable and unobstructed manual access is necessary. In particular, such a device is needed where it is necessary for a surgeon or other person to have generally open manual access to the area, yet where protection is required to prevent fluids such as blood from spraying into the face of the person and to prevent other fluids in the form of aerosols or the like and containing infectious material from escaping into the room surrounding the area.
The present invention is especially useful in the medical area for preventing the escape of harmful substances from the site of medical procedures such as surgical incisions, and the like. Harmful substances of concern in the medical area include, but are not limited to, blood and other body fluids (which often form fine aerosols in the air during procedures requiring drilling or cutting), small particles of skin, fat or muscle tissue and bone particles which are contaminated. Such substances may be contaminated by hepatitis, acquired immune deficiency syndrome (AIDS), or other transmittable diseases. Medical procedures especially dangerous to operating room personnel are those using endoscopes and bone cutting devices such as drills, reamers, saws and similar devices which may cause harmful substances to become airborne. Such airborne substances may come in contact with an open cut, a mucous membrane, or the like of the medical practitioner such that the practitioner becomes infected or contaminated by the substances.
Currently, surgical garments and masks are used as the primary protection for operating room personnel. Surgical garments and masks are not intended to, and do not prevent, the spread of harmful substances and organisms to all parts of the general operating room environment and do not protect certain parts of the practitioner. For example, such equipment often does not protect the eyes and other exposed parts of the body of operating room personnel from contact with fluids in the form of airborne aerosols including bone particles and liquids or from direct sprays, streams, or splashes of liquids. Infections and contagious body fluids are of particular concern, especially in the region of the head.
A second category of protective devices in use in the medical area is protective hoods incorporating a vacuum system used to draw away anesthetic gases from the mouths of patients during oral surgery and dentistry. Typically, the hoods are mounted on the end of a free-standing boom or on an arm attached to a dentistry chair. In operation, the dentist or oral surgeon positions the hood over the mouth of the patient during or after administration of anesthesia and activates the vacuum generation means to evacuate the gases.
Such hoods are limited in use and there are numerous limitations in the ability of these hoods to be adapted to protect medical and dental personnel from airborne infectious material emanating from the patient in a general operating room environment.
First, the hoods are limited in size as they are intended to remove only the small amount of gases such as those present during oral surgery and dentistry. The small size of the hoods limits the adaptability thereof to provide a sufficient physical barrier to block streams and sprays of body fluids and to contain the airborne particles generated during large scale surgical procedures such as joint replacement. Enlarging the size of the physical barrier would generally require abandonment of the current support structure for one similar to that of the present invention. Additionally, the dental hoods have a centrally located vacuum system and do not provide vacuum around the periphery of the hood, providing only incomplete protection against the escape of harmful gases and the like. Again, enlarging of the size of the dental hoods for use in general surgery and the like would require substantial redesign of the evacuation system.
Second, the hoods are not completely or substantially transparent, generally containing only a small window, if transparent at all. If the hoods were enlarged for surgical use and the like, the visual obtrusiveness of the hoods would significantly impair the ability of surgeons and support staff to have unobstructed access to the incision, as maximum protection is afforded only when the hood is positioned in close proximity to the incision and extends over a wide area.
Finally, as mentioned earlier, the hoods provide only a single vacuum aperture. A single vacuum aperture would not have the capability to provide a vacuum barrier around the perimeter of an area contemplated to be isolated and, consequently, it would be difficult to contain gases with such a device.
A third type of protective device in use in the medical area is an autopsy table incorporating a series of variable position vacuum ducts along the sides of the table, or alternatively, air supply ducts on one side of the table and vacuum ducts on the opposing side. In operation, the ducts draw a flow of air across the table so as to vent away noxious gases. At the head of the autopsy table, two opposing ducts may be positioned at the same height and a transparent table placed thereon.
Limitations of the autopsy table with respect to adaptability for the purposes of the present invention include the lack of vacuum ducts around the entire perimeter of the site of the medical procedure. Such openings in the vacuum barrier provide routes of escape for gases and aerosolized liquids not captured in the cross-flow due to obstructions of flow such as those occurring when persons reach into the cross-flow. Secondly, access to the site is limited on two sides due to the vacuum ducts and supplies that effectively form an access barrier. Additionally, the angle of the table is not variable and the configuration is not portable or free-standing.
Certain other conventional protective devices provide only a physical barrier or only a vacuum barrier but not a combination of the two. Those providing only a physical barrier generally are either too obtrusive to the surgeon's work area or do not prevent the escape of gases and vapors into the general operating room environment. For example, surgical garments that resemble astronaut's space suits which protect only the person wearing it provide no protection for the environment or others. Protective devices generating only vacuum to draw airborne substances, as is obvious, provide no physical barrier to streams or sprays of fluids.
Finally, vacuum devices currently in use and having self-contained vacuum source are often limited in application, as such devices incorporate no means for the containment, destruction, or safe evacuation of contaminants. Such devices are inappropriate for protection from hepatitis and AIDS as those viruses are dangerous in low concentrations and could be carried to remoter sites by an evacuation system that does not remove contaminants from the gas stream. Devices which merely dillute the concentration of toxic substances are clearly inadequate for the task of removal of infectious materials from the air.